Iray warning

Random

Hi. I have a new GeForce 1660 card but occassionally the render engine defaults back to cpu only. I look in the log file and there are warnings, like one I was doing today:

Iray [WARNING] - MATCNV:RENDER ::   1.0   MATCNV rend warn : At 'DS_Charlene Hair Genesis 3 Female__Side2_30ba_20923.volume.absorption_coefficient': unsupported function call: 'operator/(color,float)'

Is there a list of iray warning problems and how to fix them? And specifically here, do I just change the hair to one that works or is there something I can do to fix this?

algovincian

Warnings usually aren't fatal, which is why they are warnings and not errors. Are you sure you didn't run out of VRAM, and that's what caused the drop to CPU?

- Greg

Random

The log file says it needs 6gb and only has 4.9. It suggests switching from WDDM driver to TCC driver. And then it says iray photoreal CPU fallback is enabled. So not enough vram.... What are the 2 drivers mentionned and how do I switch? My 1660 card has 6gb vram. Is it that much better to have 8gb. I can return the card for one with 8 but not sure if I want to spend the extra $$$. Also, if I uncheck Optix in the advanced settings, will that help on this card?

algovincian

You can't if you're driving a display, and I don't think you can on a GeForce card unless it's a Titan anyway.Optix Prime (not Optix, which is different) did include the usage of a bit more VRAM in an effort to speed things up, but I believe it's no longer used in the curent Iray version used in DS.

Here's a couple of links that may be worth reading:

https://devtalk.nvidia.com/default/topic/959472/cuda-setup-and-installation/how-to-know-what-cards-allow-tcc-mode-/post/4958413/#4958413

https://www.daz3d.com/forums/discussion/335016

- Greg